Are the orcas starving?
As salmon runs decline, killer whale numbers take hardest hit since 1990s
Showing signs of starvation as salmon runs faltered up and down the West Coast, Puget Sound's orca population lost seven of its number over the past year, bringing the population to just 83, anxious scientists reported Friday.
The development marks the biggest reduction in the orca population since a series of bad chinook salmon seasons in the 1990s battered the killer whales' numbers.
Revealing the degree to which the orcas are interrelated to a far-flung marine ecosystem, the collapse of California's Sacramento Valley chinook run seems likely to be partly to blame for declining killer whale numbers, said Ken Balcomb, founder of the Center for Whale Research on San Juan Island.
The same fishery collapse off the California and Oregon coasts shut down salmon fishing this year for humans, too.
"We know that we're having bad chinook years, and every episode of bad chinook years, the (orca) population declines," Balcomb said. "It's like if you don't feed your pets -- they don't survive. ... They start losing body fat. They're like an old sawhorse."
Of particular note: the death of two reproductive-age female orcas in the space of a year. They usually survive at the highest rate of any orcas, with the chance of death in any given year only about 1 percent.
"That's unusual," said Brad Hanson, an orca biologist with the National Marine Fisheries Service in Seattle. "That's a bit disconcerting."
Scientists aren't predicting much better salmon numbers next year -- a forecast that could lead to more orca deaths. Females give birth in the winter, when food supplies are lowest. Yet that's also when they must lactate, which requires extra food energy.
Studies have shown that orcas have a strong preference for chinook salmon, pursuing other prey only when their primary food source is scarce. That makes scientists wonder whether there is something particular about chinook salmon that the orcas need to thrive.
Two of the orca families -- L and K pods -- have been seen in recent years feeding off the California coast in the winter. That was unheard of before early this decade, leading scientists to speculate they are driven to swim hundreds of miles just to meet their minimum nutritional requirements.
Then last winter, they likely found many fewer salmon -- even after an energy-draining swim to California.
Experts believe the population of the J, K and L pods that frequent the San Juan Islands and Puget Sound probably originally numbered between 100 and 200.
"Eighty-three is low. The real number that's of concern is that we only have about a dozen reproductive females," Balcomb said.
It's conceivable that one or more of the missing orcas might have wandered off on its own and is still alive. But orca scientists doubt that because it's only been documented happening two times in history. Other than that, orcas always have stayed with their families. Researchers are pretty sure all seven are dead -- and it makes sense, because supplies of their favorite food were so low.
The two recently deceased females were Blossom, also known by the scientific notation J-11, and Splash, also known as L-67. The latter showed signs characteristic of starvation -- particularly a depression behind her skull where blubber should be. The condition is known as "peanut head." Disease could be another factor.
Another recently deceased orca, known as L-21 or Ankh, was thought to be 58 when she disappeared. In general, orcas enjoy life spans similar to humans and become reproductively active on a similar timeline as well.
Others among the dead include two born in the past year or so. Loss of babies is not nearly as unusual as the deaths of adults in what should be the prime of their lives.
Fred Felleman, an activist who began studying the orcas in the 1980s, said back then they seemed to have little trouble finding food.
"We used to have whales that would rest in groups at the surface, flopping around like lions on the Serengeti sitting under a tree," he said. But now they are underwater hunting more and, "I've watched a steady progression over the years of the whales getting more and more dispersed. ... As the prey became more diffuse, they had to spread out."
In recent years, scientists have noted in the orcas extremely high levels of chemicals known to interfere with reproduction, finding food and other functions.
It's hard to say exactly what's killing the orcas, Hanson said. Sure, it's clear they're sometimes not getting all the food they need. But what happens next?
There's evidence that the orcas in times of low food supplies begin to burn their fat supplies -- just like humans. They, too, are mammals.
But scientists know the fat is where PCBs and other long-lived industrial chemicals are stored. Do these chemicals, once freed, have some other effects? Studies on dolphins showed they caused reproductive problems. Studies on Puget Sound harbor seals showed the chemicals made the seals more likely to get sick. Dolphins and seals are mammals, too.
Hanson and other scientists are trying to assess the health of the orcas by collecting their waste and what's in the breath they exhale through their blowholes.
"We're really trying to look at what sorts of stressors are these animals up against," Hanson said, "because right now the animals disappear and we really don't understand what's happening.
"Is this directly starvation? Maybe, maybe not. There might be something else going on."
Hanson took samples of L-67's skin and blubber, which will be tested for disease.
Decades ago, orcas were regarded as pests and even shot at. Later, in the 1960s and 1970s, their population was reduced drastically by captures, as the marine mammals were shipped off to aquariums and water theme parks. Their number dipped to 71 by 1976, when Balcomb began to do the first census of the animals.
They reached a population peak of 97 in 1995, before a series of salmon-poor years sent their numbers plummeting to a low of 79 in 2001, a Center for Whale Research census showed.
Officially, the orcas are counted each July 1. So several won't be recorded as missing until next summer. Some also are born and die before the official count.
Seven Puget Sound orcas most likely died this year
Modern population peak
Reached in 1995, before a series of salmon-poor years sent their numbers plummeting to a low of 79 in 2001
What experts believe the J, K and L pods originally numbered
P-I reporter Robert McClure can be reached at 206-448-8092 or email@example.com. Read his blog on the environment at datelineearth.com.